Analysis of minerals



Y Dec. 23, 1941. v ALEXANDER EIAL 2,266,840

ANALAYSIS 0F MINERALS Original Filed Aug. 31, 1936 IN V EN TORS.

\ H. L. ALEXANDER H. 1. ouPONZ' AND BY n45. OULk I AT'TOR EY.

Patented Dec. 23, 1941 umrso STATES P TENT oFrIcE ANALYSIS MINERALS Original application August 31, 1936, Serial No.

98,819. Divided and this application 1939, Serial No. 263,082

3 Claims (01. 209-112) This invention relates to an-apparatus and method for determining the percentage of a valuable mineral such as coal in a mineral product which may contain coal and ash in varying amounts. In illustrating the apparatus and method reference will be made to coal and slate,

but it should be understood that the use of our method and apparatus to determine the percentage of ash in coal and the percentage of coal in slate is merely illustrative, and both apparatus and method are equally applicable for determining the percentage of any valuable mineral in any other naturally occurring mineral product such as an ore or mineral mixture.

The apparatus as illustrated is particularly adaptable for use in connection with a mineral separation apparatus wherein coal is separated from slate and from middlings (known in the coal industry as bone) as illustrated in our copending application Serial No. 98,819, filed August 31, 1936. The present application is a division of said copending application.

The apparatus and the method herein described are especially valuable for determining the percentage of coal in the sinks. If the separation of minerals by' flotation methods the term sinks normally denotes that fraction of the product supplied to the flotation chamber which will sink in any given flotation medium. In the coal industry the sinks are the more slatey fraction containing, however, some coal. The apparatus and method herein described are also valuable for determining the percentage of slate in the floats, i. e., in that portion of the mineral fed to the flotation chamber which floats in any given flotation medium. This is, in coal separation methods, the coal of relatively low slate or ash content. In other words, the apparatus disclosed herein, when employed in conjunction with the method herein described, providesmeans for determining the ash content of the clean coal. Similarly, the inert percentage present in any valuable mineral other than coal may also be determined. The value of determining this percentage of inert or undesirable material, as an example the ash content of the clean coal, is that it permits adjustment of a larger mineral separation system wherein minerals such as coal are separated by flotation methods so that the middlings may be divided to best advantage. The term "middlings in mineral separation practice involving flotation methods means that product intermediate in gravity between the lighter fraction such as coal, which has a decided tendency to float, and the relatively March 20,

heavier fraction such as slate or the material of high slate content which has a definite tendency to sink. The determination of ash content is not, however, desirable only in the operation of mineral separation systems, as such knowledge may be valuable in a number of other instances. An object of this invention is, accordingly, the provision of an improved apparatus .employing a more effective and novel method for the determination of the ash content of coal, or the percentage of inert or undesirable material in any valuable mineral of which coal is one example. A

further object of this invention is to permit the determination of this ash contentby determining the percentage of coal in the sinks and the percentage of slate in the floats, when coal is the mineral product in interest, the described apparatus constituting a superior and improved equipment to permit such determinations. These and still further objects of our invention will be apparent from the ensuing disclosure of a preferred embodiment thereof.

In the drawing, Fig. 1 represents a view partly in section and partly in elevation of our improved apparatus for accomplishing the objects noted. Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1 and looking in the direction denoted by the arrows. Fig. 3 represents a scoop, this constituting one of the elements utilized in conjunction with the apparatus, as shown in the dotted lines of Fig. 2. Fig. 4 represents an enlarged detail of the hinge connection.

In these figures the numeral I5 indicates generally a long trough, made preferably of some chemically resistant metal. This trough is divided into a series of chambers by the dividing walls I50. Trays, represented generally by the numerals 'I5I, which have foraminous bottoms I52 and preferably solid sides are positioned within the chambers or compartments. Each compartment of the trough'is, provided with a tray which conforms generally with the shape of the compartment. These trays I5I are pivoted at one end to the trough, conveniently by the arrangement shown in Fig. 4. As shown in that figure there are attached to the outer edges of the trays 'I5I the U-shaped members I53 which are secured by welding or otherwise to the outer edge of the tray. A pipe I54, or other circular member, is attached to and forms the edge of trough "I5. Bolts I55 pass through the ends of the U-shaped members I53. Handles I56 are attached to the lip of the tray I5! opposite the pivot I55. Element I51 represents stop members so placed that they contact the edge of the -f specific gravity 1.9.

trays I51 and prevent them making contact with the bottom of the trough I5. Pipes I58 provided with the valves shown permit drainage of the compartments. Stop bars I59 are placed approximately midway oil and running the length of the sides of the trays I51, A scoop I60 having a roraminous bottom l6l and handle 162 is provided. The trough I is supported by supports I63. There is also provided a. shelf I64 running lengthwise and in front of trough 15, this shelf being provided with an edge or turned-up portion I65 for preventing the escape of liquid. The shelf is also provided with a drainage channel for liquid, I66. Pipe I61 is provided for removing this liquid from the drainage channel. Screen I68 prevents the escape of solids through the drainage system. A means for regulating the a temperature of the bath, such as the steam line 110, may also be provided.

The apparatus shown -wi ll ordinarily be provided with possibly ten compartments. In utilizing'this apparatus. to determine the various factors needed for determination of ash content, each compartment is first filled to equal depth with a liquid. The level of liquid in the apparatus is represented by the line I69. The first compartment, for example, may contain a liquid The liquid in the next adjacent compartment may have a specific gravity of 1.85; that in the next adjacent compartment 1.8; that in the next adjacent compart-- ment 1.78; that in the next succeeding compartment a gravity of 1.76, etc. The specific gravities of these liquids are so chosen as to give the maximum amount of information with respect to the particular coal or other mineral being treated in the process at that particular moment. A sample to be tested is secured, this sample being taken, for example, from that coal which is discharged from the water-sealed conveyor of our copending patent application previously referred to, Serial No. 98,819. A weighed sample of this coal or other mineral product is placed in the first compartment. Assuming that the specific gravity of the liquid in. this compartment has been correctly chosen for the first test, a considerable portion of the charge will sink and the remainder will float. The operator then-takes scoop I60, inserts its nose within the tray as shown in Fig. 2, slides it across the runners I59, which are at equal depth in each compartment, and withdraws the floats. The liquid is allowed to drain back through apertures I6! in the 150- raminous bottom of the scoop and the floats are placed in the next tank wherein-the specific gravity of the liquid is somewhat lower. This procedure is continued until the sample has been divided according to specific gravities. By pulling on handle I56 each tray I5l may be pivoted about pipe I54, draining through holes I52 back into the trough I5, and the sunken material may be dropped onto apan or other suitable container placed on the table I64.

When used in conjunction with a mineral separation system employing flotation methods, such as that described in our previously referred to copending application, the system is first calibrated by making ash determinations with the particular type of coalor mineral which is being separated. A determination is first made of the specific gravity of the mineral material which is being separated in order to determine the specific gravity of the parting liquid to be employed in the separating chamber. After operation has commenced, and coal is being separated from the slate, samples are taken of both the sinks and floats and ash determinations are run thereon in order to calibrate the system. Thereafter determination of the specific gravity of any particular sample may be secured by plotting subsequent tests against the control. In this way the ash content of the slate or fraction which sinks, and the slate content of the coal, the more readily floated traction, may be determined. From the information thus obtained adjustment may be made in the main mineral separation chamber in order to vary the percentage of slate in the coal. In each instance, an accurate check on the distribution of middlings, or mineral intermediate between the floats and the sinks, will be given. If the specific gravities range between that in which pure coal alone will float and that in which slate alone will sink, the specific gravities of the samples which sink in succeeding baths will be in direct relationship to their respective quantities oi coal and stone.

In utilizing this apparatus a solution of zin chloride is a satisfactory agent because it may be easily diluted to precise specific gravities. However,- any other satisfactory liquid may be 'used which will give a number of liquids or baths of varying specific gravities. It is evident that having determined the distribution of the middlings as actually distributed by a mineral separation apparatus, such as the apparatus more particularly adapted for separating coaldescribed in our copending application, changes maybe promptly made in the setting of the apparatus so that another and more favorable distribution can be made therein 11 such is desired.

It' should be remembered that the device, as disclosed, is suitable for the determination of the percentage of any valuable mineral, such as any of those mentioned in our copending application, in a mineral product obtained in a native condition and containing the desired mineral in admixture with indigenous impurities. The apparatus and the methods for using it have been described in conjunction with the ash determination of coal simply as illustrative, although this constitutes an important though not exclusive use of our apparatus and method.

As various changes may be made in the apparatus and process as described, which changes will nevertheless come within the scope and spirit of our invention, that invention should not be restricted to preferred embodiments given merely as illustrative or to exact details, except as necessitated by the prior art and the appended claims.

We claim:

1. Mineral analysis apparatus comprising a trough transversely divided into. a plurality of compartments, each compartment being adapted to hold a liquid of definite specific gravity, a plurality of trays positioned within said compartments. there being positioned one tray in each compartment, said trays being provided with liquid drainage means in a bottom portion thereof and being pivotally mounted about one edge or said trough in order that they may be tipped so that mineral samples may be more readily removed therefrom, means attached to each tray the entire length of said trough for removing mineral samples removed from said trays.

- ments. .each compartment being adapted to hold.-

ciflc gravity, valve-controlled means for removing said liquid from said compartments, trays positioned within said compartments, said trays being adapted to retain therein mineral samples which sink in the liquid present within said compartments, said trays being pivotally mounted about one edge or said trough in order that mineral samples therein may be readily transported outside or said trays, handle means attached to said trays and adapted for tipping said trays about said pivotal mounting in order to remove mineral contents therefrom, said trays being provided with means to permit the escape oi liquid present therein into said compartment within which each tray is positioned, means for heating the liquid in said compartments, a guide rail positioned within each tray and located a substantial distance below the normal liquid level, said guide rail extending generally horizontally and longitudinally of said tray, and a shelf secured to said trough and provided with liquid drainage means for retaining the mineral samples removed from said trays.

3. Mineral analysis apparatus comprising, in

combination, a trough having a generally arcuate form in cross section, said trough being divided transversely into a plurality of comparta liquid or a definite pecific gravity, means for removing said liquid from said compartments,

trays of generally arcuate cross section positioned within said compartment closely adjacent the walls of said arcuate trough, said trays being adapted to retain therein mineral samples which sink in the liquid present within said compartments and being pivotally mounted about one edge of said arcuate trough in order that mineral samples present in said trays may be readily transported outside of said trays by pivotal movement about said edge or said trough, handle means attached to said trays and adapted for tipping said trays about said pivotal mounting in order to remove mineral contents therefrom, said trays being provided with means to permit the escape of liquid present therein into said,

compartment within which each tray is positioned, a conduit secured to said arcuate trough and serving to permit passage of a fluid heating medium for heating the liquid within said compartments, a guide rail positioned within each tray and located a substantial distance below the normal liquid level, said guide rail extending generally horizontally and longitudinally of said tray, and a shelf secured to said trough and provided with liquid drainage means for retaining the mineral samples removed from said trays.

' HENRY L. ALEXANDER.

HUBERT 1. no PONT. WILLING B. FQULKE. 

